Process for the production of photographic images by color development



Patented June 14, 1949 UNITED STATES PATENT OFFICE PROCESS FOR THEPRODUCTION OF PHOTO- GRAPHIC IMAGES BY COLOR DEVELOP- Philibert RaymondMerckx, Mortsel-Antwerp, Belgium, assignor to Gevaert Photo-Producten N.V., Mortsel-Antwerp, Belgium, a company of Belgium No Drawing.Application February 26, 1948, Se-

rial No. 11,324. In- Belgium August 3, 1945 Section 1, Public Law 690,August 8, 1946 Patent expires August 3, 1965 8 Claims.

This invention relates to the production of photographic images by colordevelopment, and more particularly to a new group of color couplers.

It is known in the art of color development to use color couplers whichcorrespond to the following general formula wherein Y is anelectronegative group,

-. R is amino, substituted by an arylor heterocyclic group.

It is further known to use as color couplers,

' 1-2-4-oxodiazols of the following general formula e wherein X is anelectro-negative organic radical, for instance CN, alkyl-CO, aryl-CO, Yis an organic radical, hydrogen.

It is an object of my invention to provide a new process for developingreducible silver salt images.

It is also an object of my invention to provide a process for theproduction of colored photographic images.

Another object of my invention is to provide a new color developer.

Still another object of myinvention is to provide new light-sensitivesilver halide emulsions.

' A further object of my invention is to provide a colored photographicimage.

Further objects will appear from the following description.

These objects are accomplished by developing a reducible silver saltimage with an aromatic amino developing agent in the presence of acompound corresponding to the following general formula wherein Z is Oor S,

Y is hydrogen, an aliphatic-, homoor heterocyclic group eithersubstituted or not.

The reactive methylene group may also be substituted by atoms or groupswhich, on developing, easily spilt-off. such as for instance bromo.

It is sufficient that on development, a com-[2-p-nitrophenyl-1,3,4-oxodiazolyl (5) acetonitrile ll g N 02- C C Hz-CN 1,3,4-oxodiazolyl-2,5-di-acetonitrile N N CN-GHr (LBOHBON[2-p-tolyl-1,3,4-thio diazolyl (5) ]acetonitrile N Gaga These nitrilesmaybe prepared for instance from NN'-substituted hydrazides having atleast one CNCH2-CO group. For instance for the preparation of zolyl (5)]acetonitrile, 15.3 g. of

are mixed with 15 cm. phosphoroxy-chloride.'

This mixture is heated for two hours on an oil 7' bath at -140 C. Thethick Oil obtained is poured upon 250 g. finely cracked ice.

The brown precipitate formed is purified by boiling with alcohol.

It is noteworthy that, depending on the kind and substitution of thegroup Y, these new color couplers yield the wideliest different tones.Also the substitution of the oxygen atom in the nucleus by S enables theshifting of the absorption maximum.

In practicing my invention, the new color couplers may either directlybe added to the photographic colloid layer, either before or aftercoating so that the colored image is formed by developing with anaromatic developer, or the colored image may be obtained by developingthe photographic image with an aromatic developer which contains one ofthe above-defined color couplers.

The colloid layer to which the color coupler is added, may be alight-sensitive silver halide [2-p-nitrophenyl-1,3,4-oxodia- Adeveloping bath for obtaining color images according to my invention is"the following:

A N ,N-diethylparaphenylenegdiamine Z is a member selected from thegroup consisting of.0 ands,

.is a member se'lectediirom the group censisting of aliphatic-, homoandheterocyclic groups.

3. Process for the production of photographic color images by coiordevelopment, which comprises developing with a primary aromatic aminodeveloping agent a reducible silver salt image in a light-sensitivesilver salt emulsion containing a compound of the following generaliormula:

Nr=N H g 1-0 -CH2GN z "wherein Z is amember selected from the groupconsisting hydrochloride grams 5 Sodium sulphite (cryst.) do Sodiumcarbonate (cryst.) do 100 Sodium hydroxide do 1 Water cm'. 1000 B C n uNO 0 OCH:CN ..grams 1 Acetone cm. .30

. Before using,B is added to A.

7 My invention may be used for obtaining colored photographic imagesupon plates, ,paper or film, coated with a light-sensitive silver halideemulsion. "The color developing process may be used for developingphotographic material with one or more light-sensitive layers coated onone side or on Jooth sides 26f the support.

The silver image-termed during the development, can easily be removed bytreatment in a bleach-bath. The bleach-bath used, however, is notallowed to exert anoxious influence upon the colored image.A'bleach-hath of potassium ferricyanide and sodium thiosulphate, removesthe silver without damaging the color image.

I claim:

1. Process for the production of photographic color images "by colordevelopment, which comprises developing a reducible silver salt imagewith a primary aromatic amino developing agent in the presence ofacompound of the following general formula:

IN--=N ll Y-G -.GH r-.GN

. z wherein Z is a member selected from the group consisting of O and S,

Y is a member selected from the group consisting ofaliphatic-,homoandheterocyclic groups.

'2. Process for the productionof photographic color images ,-by :colordevelopment, which comprises developing a reducible silver salt imagewith a developer containing a primary aromatic amino developing agentand a compound of the following general formula:

wherein of 0 and S, Y'is a member selected from the group consisting ofaliphatic-, homoand heterocyclic groups.

4. Color photographic developer containing .a primary aromatic aminodeveloping agent and 1a com-poundof thefol-lowing general formula:

N Y-Ji Ji-cieT-cN Z wherein Z is a member selected from the groupconsisting of O and S,

Y is .a member selected .from the group nourishing of aliphatic-,homoand heterocirclicsgroups.

taining a compound of the .following general formula IccEPoN wherein Zis a .memberselected from the group consisting of :0 and S, Yisamemberselected from the group consisting of aliphatic-,homoandheterocycl-ic groups.

RHILIBERT RAYMOND MEECKK.

.BEFERENCES CITED The following references are of record in the file iOfthis patent:

FOREIGN PATENTS Country Date Number F'rance. s..,... --w- Oct. 10, 1938

